My research involves determining the nature of the interactions between the small Tim (Translocase of the inner membrane) protein complexes and the substrate. The inner membrane space of the mitochondria contains the Tim9p-Tim10p and the Tim8p-Tim13p complexes. Through previous research Professor Koehler's group has shown that the small Tim proteins bind to the membrane spanning domains of inner membrane proteins. My goal is to understand how the small Tim proteins bind to their substrates. By developing binding assays I can determine the nature of interactions and binding kinetics between the substrate and the small Tim complexes. Some of the initial methods proposed include surface plasmon resonance, intrinsic fluorescence, and mass spectrometry. Probing the nature of interactions between the small Tim complexes and their substrates via biochemical and biophysical techniques will aid in the comprehension of how defects in mitochondrial assembly lead to disease.